Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
A proximity sensor device typically includes sensor electrodes that are driven with signals for capacitive sensing. Receiver circuitry receives resulting signals from the sensor electrodes for determining positional information of one or more input objects near the proximity sensor device, if any are present. The receiver circuitry generally has a dynamic range that determines the range of signal strengths of the resulting signals from which meaningful positional information may be derived. If the dynamic range of receiver circuitry is exceeded, meaningful data may not be extracted from signals received as a result of driving the sensor electrode for capacitive sensing. For example, clipping and distortion may occur along the signal path if the amplitude of the received signal exceeds the range limit of the receiver circuitry.